Re: How to check if a function exists within a package?

To check if something exists use exists. ;)

use strict;
use warnings;

require ('Encode.pm');

if (exists &Encode::encode) {
    print "Exists\n";
} else {
    print "None such\n";
}
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Prints:

Exists
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Perl reduces RSI - it saves typing

Comment on Re: How to check if a function exists within a package? Select or Download Code

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Re^2: How to check if a function exists within a package? by ikegami (Patriarch) on Sep 08, 2008 at 01:29 UTC
`defined` vs `exists`: `sub foo {} sub bar; my @names = qw( foo bar baz ); local $, = "\t"; local $\ = "\n"; print('', @names); print('exists', map { exists(&$_) ?1:0 } @names); print('defined', map { defined(&$_) ?1:0 } @names);` [download] `foo bar baz exists 1 1 0 defined 1 0 0` [download] You can't call the ones that exist but aren't defined, so `defined` is probably a better choice. `>perl -e"sub bar; bar()" Undefined subroutine &main::bar called at -e line 1.` [download]	[reply] [d/l] [select]

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Re^2: How to check if a function exists within a package?
by ikegami (Patriarch) on Sep 08, 2008 at 01:29 UTC

defined vs exists:

sub foo {}
sub bar;

my @names = qw( foo bar baz );

local $, = "\t";
local $\ = "\n";
print('',                                  @names);
print('exists',  map { exists(&$_)  ?1:0 } @names);
print('defined', map { defined(&$_) ?1:0 } @names);
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        foo     bar     baz
exists  1       1       0
defined 1       0       0
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You can't call the ones that exist but aren't defined, so defined is probably a better choice.

>perl -e"sub bar; bar()"
Undefined subroutine &main::bar called at -e line 1.
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[reply]
[d/l]
[select]